Sports nutrition Dr. WAFAA FAHMI ASISSTANT PROFESSOR OF PUBLIC HEALTH AND NUTRITION NATIONAL NUTRITION INSTIT
GoalsSports nutrition has many goals to enhance performance.
GoalsFirst, it improves performance by improving body composition, which increasesspeed, quickness, mobility, and strength.
GoalsSecond, it will help the speed of recovery, which will in turn create more capacity forpracticing and competition asthe body is becoming more fit and adjusted .
Goals Third, it will allow one to increase energyfor both practice and competition, which will definitely help ones performance. Strategic diet will also increase immunity, allowing one to stay healthy and be able to continue and intensify practice and training.
Factors Influencing Nutritional RequirementsDiffering conditions and objectives suggest theneed for athletes to ensure that theirnutritional approach is appropriate for theirsituation.
Factors that may affect an athletes nutritional needsType of activity (aerobic vs.anaerobic), gender, weight, height, body massindex, workout or activity stage (pre-workout, intra-workout, recovery), and time ofday (e.g. some nutrients are utilized by thebody more effectively during sleep than whileawake).
Anaerobic ExerciseDuring anaerobic exercise, the process of glycolysisbreaks down the sugars from carbohydrates forenergy without the use of oxygen. This type ofexercise occurs in physical activity such as powersprints, strength resistances and quick explosivemovement where the muscles are being used forpower and speed, with short time energy use.After this type of exercise, there is a need to refillglycogen storage sites in the body (the longsimple sugar chains in the body that storeenergy), although they are not likely fullydepleted.
Anaerobic ExerciseTo compensate for this glycogen reduction, athleteswill often take in a large amount of carbohydratesin the period immediately following exercise.Typically, high glycemic index carbohydrates arepreferred for their ability to rapidly raise bloodglucose levels. For the purpose of proteinsynthesis, protein or individual amino acids areingested as well. Branched-chain amino acids areimportant since they are most responsible forprotein synthesis
Anaerobic ExerciseOften in the continuation of this anaerobicexercise, the product from this metabolicmechanism builds up in what is called lactic acidfermentation. Lactate is produced more quicklythan it is being removed and it serves toregenerate NAD+ to the cells where its needed.During intense exercise when oxygen is not beingused, a high amount of ATP is produced and pHlevels fall causing acidosis or more specificallylactic acidosis.
Anaerobic ExerciseLactic acid build up can be treated by stayingwell-hydrated throughout and especially afterthe workout, having good cool down routineand good post-workout stretching
Aerobic exerciseIn aerobic exercise, oxygen is needed to supplyenergy and this oxidation helps neutralizesfree radicals. After aerobic exercise, it isnecessary to refill the glycogen stores in theskeletal muscles and liver. There is a 30-minute window after exercise critical tomuscle recovery
Aerobic exerciseBefore doing anything else, drink something forrecovery. Liquids are ideal (like water, juice orsports drinks) and as mentioned above, low-fat milk and chocolate milk are effectiverecovery beverages because of their ideal 4:1combination of carbohydrate and protein thatfuels and replenishes muscles the best
Aerobic exerciseis slow so that the body can work throughendurance exercises such as long distancerunning or swimming because these activitiesrequire constant use of oxygen to supplyenergy.Fats (lipids), carbohydrates(sugars), proteins and other substrates aredifferent substances the body can utilize tomake sufficient ATP energy
Aerobic exerciseIn addition, men and women have differentways of metabolizing these substrates. It hasbeen found that women oxidize more lipids(fat-burning), less carbohydrates, and lessamino acids than do men during enduranceexercise.These differences may be linked tothe higher levels of female sex hormones 17-beta-estradiol, estrogen and progesterone.
Aerobic exerciseIn addition, women should carbohydrate-load byconsuming more than about 8 g ofcarbohydrates per kg per day toovercompensate for lower habitual energyintake consumed during long aerobic activityfor optimal performance.
Factors Influencing Nutritional RequirementsAlso, gender may lead to differences in the"Fight or flight" hormone epinephrine(commonly known as adrenaline). Duringexercise, men have higher sympathetic(sympathetic nervous system) activity duringexercise, stimulating epinephrine andnorepinephrine, making the concentrationshigher in the blood
Factors Influencing Nutritional RequirementsAdrenaline is a natural vasodilator, (which allowsoxygen to flow faster and reach the musclesfaster through blood vessels (especially arteries)it increases heart rate, dilates the pupils andconstricts arterioles in the skin andgastrointestinal tract. The sex hormones may bethe link to the gender differences inmetabolism, causing women to needcarbohydrates (sugars) for endurance and formen to gain more epinephrine during exercise.
Eat a Balanced Diet Each Day• To exercise consistently, you need to provide a good supply of high-quality energy to your working muscles. The easiest way to to this is to eat a balanced breakfast and continue eating a variety of high-quality foods throughout the day.• Carbohydrate in the form of glycogen is the fuel that makes exercise possible, so adequate carbs must be eaten each day if you hope to train consistently. Protein and fat also have a place in your diet and should be consumed daily. In general, each meal should contain a varied combination of carbohydrates, protein and fat.• If you arent sure if you are getting the proper nutrients in your daily diet, check out Calorie Count to create a profile and analyze your diet.
Several Hours Before You WorkoutThe pre-exercise meal will vary depending upon your exercise style. If you workout in the evening, lunch should include easily digestible foods high in complex carbohydrates, such as pasta, breads, fruits and vegetables. A big salad with a small amount of protein works well. Select a small amount of lean meat such as chicken or fish, and experiment with what works best for you.If you exercise first thing in the morning, youll probably feelbest if you eat a light breakfast of fruit, toast, or an egg.Again, everyone is different, so experiment with whatworks best for you. Regardless of what you choice toeat, you should drink plenty of water before and during
Thirty Minutes Before You Workout• Depending upon the type and duration of workout you do, youll want to eat a small snack and drink some water a half hour before you get going. Trail mix is great for aerobic workouts over 60 or 90 minutes, but if you are going hard for thirty minutes, you probably only need a half of an energy or granola bar, a large banana, a few graham crackers, fig bars, or pretzels. For a shorter workout, you may not want to eat anything at all, but can get a few calories from drinking about 8-10 ounces of a sport drink.• You should also start drinking water before your workout so youve consumed about 6-12 ounces in the the hour before your workout
During Your Workout• Proper hydration during exercise depends upon the intensity and duration of exercise, the fitness of the athlete, and weather conditions. In order to simplify the recommendations, a good starting point is to drink 8-10 fl oz of water every 15 min during exercise.• If exercising longer than 90 minutes, drink 8-10 fl oz of a sports drink every 15 - 30 minutes. Exercising for more than about 90 minutes usually requires that you replenish lost carbohydrates.If your workout is less than an hour, odds are you dont •nee
Hydration After Your WorkoutAfter your workout, drink enough water to replace water lost through sweat. The best way to determine this is by weighing yourself before and after exercise. For every pound of body weight lost, youll need to consume about 3 cups of fluid.Another way to determine how much liquid toconsume is to check the color of your urine.Dark, concentrated urine may indicatedehydration. Your urine should
Eating After Your Workout• The post-exercise meal should be eaten within two hours of a long or intense workout in order to replenish glycogen stores for continued exercise. While research shows eating 100-200 grams of carbohydrate within two hours of endurance exercise is essential to building adequate glycogen stores, eating a combination of both carbohydrate and protein seems to be an even better option. Studies have found that a 4:1 ratio of carbohydrate to protein seems to the ideal combination of nutrition. And although solid foods can work just as well as a sports drink, a drink may be easier to digest make it easier to get the right ratio and meet the 2-hour window.